title: Neuronavigation-guided endoscopic and hodotopic approach to an arachnoid cyst.
abstract: BACKGROUND
  Arachnoid cysts are intraarachnoid benign cystic lesions filled with cerebrospinal fluid and should be treated without incurring further morbidity to the patients.
  
  
  METHODS
  The authors present a case of a 68-year-old elderly female with a large right fronto-parieto-temporal arachnoid cyst who has been suffering from mild left hemiparesis for the past 4 years and presented with sudden onset of seizures. The 3 Tesla MR system with diffusion tensor imaging (DTI) and MR tractography of the brain showed a large right fronto-parieto-temporal cystic lesion measuring 7 × 5 × 5 cm with a midline shift of 1 cm, suggestive of an arachnoid cyst with surrounding ipsilateral white matter projection pathways and inferior occipito-frontal fasciculus or inferior longitudinal white matter tracts. The cyst was successfully treated with neuronavigation-guided endoscopic and hodotopical approach to fenestrate the arachnoid cyst into the sylvian cistern, avoiding inadvertent injury to major white matter tracts portrayed by DTI. Postoperatively, a repeated computed tomography (CT) scan of the brain revealed a smaller arachnoid cyst with correction of the midline shift. The patient was weaned off from the ventilator and her hemiplegia improved gradually.
  
  
  CONCLUSIONS
  This case report emphasizes the value of neuronavigation-guided endoscopic and hodotopic approach to fenestrate the intra-axial arachnoid cyst.
authors.affiliation: Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia 16150, Kubang Kerian, Kelantan, Malaysia.
authors.forename: Zamzuri
authors.initials: Z
authors.lastname: Idris
authors.forename: Puneet
authors.initials: P
authors.lastname: Nandrajog
authors.forename: Jafri M
authors.initials: JM
authors.lastname: Abdullah
authors.forename: Rahman I
authors.initials: RI
authors.lastname: Ghani
authors.forename: Badrisyah
authors.initials: B
authors.lastname: Idris
keywords: Arachnoid cyst; endoscopy; hodotopy; neuronavigation; tractography